i can't really critique hard because i'm not on my monitors (just some crappy desktop speakers cuz i'm out of town). the dada life one i don't know the original much but it sounds good. i really like the metal mario one, the samples are a bit too loud. sounds like a cool mix to play live, has a bit of commercial feel to it.
the drop should be more epic, way too sneaky (not the take you by surprise kind of sneaky, the oh it's here? kind) you should add a big pause and mario saying "it's a meee a m-" and cut it off with the drop or something corny like that. keep it up, and keep me updated i would like to hear the completed project
i'd link you to my stuff but i'm way too lazy to find threads. might be easier for you to just go to my soundcloud, in my sig.

keep it up